It's a big question to start any baseball season. how many innings will a team get out of its top five--or six--starting pitchers this year?
In 2021, the question is even more fraught. The abbreviated 2021 season meant that no starter went for a full season’s worth of innings, and teams were not able to have their young pitchers ramp up their workload from the previous season.
The Astros have to deal with this general problem. But they also have specific worries about the nature of their roster. With Justin Verlander out for the season after Tommy John surgery and the front office deciding to direct its off-season spending on re-signing Michael Brnatley and adding veteran arms to the bullpen, the Astros have to rely on a young but capable core of five starting pitchers.
The good news for Astros fans is that starting five looks plenty capable. It lacks the top-end arm we have gotten used to from Cy Young contenders like Dallas Kuechel, Gerrit Cole, and Justin Verlander. But it is a deep set of starters with potential upside in the four young pitchers that occupy spots 2-5. Zack Greinke is the likely opening day starter, and he is a steady and dependable veteran arm to anchor the staff.
But after those top five arms, questions arise quickly. Jake Kaplan of The Athletic identified Luis Garcia, Forrest Whitley, and Brandon Bielak as the next set of rotation candidates, Combined, they have 8 major league starts--6 by Bielak, 2 by Garcia, and none by Whitley. As Kaplan concluded, “it’s an open question as to whether the Astros have enough rotation depth.”
With depth at a premium, the question becomes even more important: how many starts and innings can the Astros expect from their top five starting pitchers. To provide an objective and quantifiable answer, I turned to the Depth Charts projections, hosted by Fangraphs. Here is what they show in chart form.
This paints a happy picture for Astros fans. These projections say that the Astros will be able to run out one of their top five starters in 83% of their games. That still leaves 28 starts for other starters, with Depth Charts projecting 11 for Whitley, 8 for Garcia, and 5 for Bielak. The Astros will need to use some of their depth to shore up their rotation, but that is to be expected. Dusty Baker is quoted in Kaplan article as saying "You hope to go the whole year with five, which never happens." But this projection says that the depth will be used to cover occasional gaps in the pitching staff.
But my read of these projections is that they paint too happy of a picture. First of all, pitching contains a ton of injury risk, both of the season-ending surgery and the take two weeks off to get your body back to normal variety. These projections can use past data to project the smaller stuff for pitchers. But it is difficult, if not impossible, to predict major injuries, and these metrics do not do that. The best we can do is to knock on wood, throw salt over our shoulders, and keep our fingers crossed as we read this paragraph.
The other thing I worry about is that these projections have the four youngest pitchers in the rotation pitching at or near their career highs for innings pitched in a season. Here’s another chart of the career high IP in a season for these guys.
I should note that these numbers include innings across multiple levels for all four players. Compare the numbers in this chart with the projections in the first chart, and you can see that McCullers, Valdez, and Urquidy are all projected to match their career highs in innings pitched. Javier is projected to exceed his by 15 innings.
Can they do it? Yes. But can they all do it. I’m skeptical.
First of all, pitcher is a dangerous business. Pitchers come down with ailments all the time, which range from "take two weeks to see if the soreness goes away" to "Welp, one pitch and he's out
The career of Lance McCullers shows the peril of expecting a full season from a pitcher. McCullers was on the disabled list in 2015, 2016, and 2017 with minor ailments, missing short periods of time each season. In 2018, McCullers finally looked healthy as he took his turn every fifth day for 22 starts, before he got a big injury. An elbow injury forced McCullers from the rotation and, after making a few bullpen appearances in September and October, he had Tommy John surgery after the 2019 World Series. McCullers missed the 2019 campaign. Pitching is a dangerous business.
So in short, expect to see Luis Garcia making a number of starts in downtown, and not just suburban, Houston this season. Let's all rub our lucky rabbit’s feet and hope that the various physical and mental ailments of Forrest Whitley are healed and that he can be effective as he debuts in the majors. We should light a candle that the magic that Brent Strom and the Astros player development has worked on Urquidy, Valdez, and Javier will apply to current minor leaguers like Tyler Ivey, Brett Conine, and Shawn Dubin. Heck, we should hope for a deadline trade for another starting pitcher to help them team get through the dog days of summer.
So while we can’t know how many innings and starts the Astros will need from pitchers beyond the starting five, we know that they will need them. And that their depth will be tested this season.